Clinical and Biomarker Findings of Neoadjuvant Pembrolizumab and Carboplatin Plus Docetaxel in Triple-Negative Breast Cancer: NeoPACT Phase 2 Clinical Trial

Importance

Addition of pembrolizumab to anthracycline-based chemotherapy improves pathologic complete response (pCR) and event-free survival (EFS) in triple-negative breast cancer (TNBC). The efficacy of anthracycline-free chemoimmunotherapy in TNBC has not been assessed.

Objective

To assess the efficacy of the anthracycline-free neoadjuvant regimen of carboplatin and docetaxel plus pembrolizumab in TNBC.

Design, Setting, and Participants

This was an open-label phase 2 clinical trial including a single group of patients with stage I to III TNBC enrolled at 2 sites who received neoadjuvant carboplatin and docetaxel plus pembrolizumab every 21 days for 6 cycles. Participants were enrolled from 2018 to 2022.

Intervention or Exposure

Carboplatin (with an area under the free carboplatin plasma concentration vs time curve of 6) and docetaxel (75 mg/m2) plus pembrolizumab (200 mg) every 21 days for 6 cycles. Myeloid growth factor support was administered with all cycles.

Main Outcomes and Measures

Primary end point was pathologic complete response (pCR) defined as no evidence of invasive tumor in breast and axilla. The secondary end points were residual cancer burden, EFS, toxicity, and immune biomarkers. RNA isolated from pretreatment tumor tissue was subjected to next-generation sequencing. Specimens were classified as positive or negative for the 44-gene DNA damage immune response (DDIR) signature and for the 27-gene tumor immune microenvironment (TIM; DetermaIO) signature using predefined cutoffs. Stromal tumor-infiltrating lymphocytes (sTILs) were evaluated using standard criteria. Programmed cell death-ligand 1 (PD-L1) testing was performed using a standard immunohistochemical assay.

Results

Among the eligible study population of 115 female patients (median [range] age, 50 [27-70] years) who enrolled from September 2018 to January 2022, 39% had node-positive disease. pCR and residual cancer burden 0 + 1 rates were 58% (95% CI, 48%-67%) and 69% (95% CI, 60%-78%), respectively. Grade 3 or higher immune-mediated adverse events were observed in 3.5% of patients. sTILs, PD-L1, DDIR, and TIM were each predictive of pCR in multivariable analyses. The areas under curve for pCR were 0.719, 0.740, 0.699, and 0.715 for sTILs, PD-L1, DDIR, and TIM, respectively. Estimated 3-year EFS was 86% in all patients; 98% in pCR group and 68% in no-pCR group.

Conclusions and Relevance

The findings of the phase 2 clinical trial indicate that neoadjuvant carboplatin and docetaxel plus pembrolizumab shows encouraging pCR and 3-year EFS. The regimen was well tolerated, and immune enrichment as identified by various biomarkers was independently predictive of pCR. These results provide data on an alternative anthracycline-free chemoimmunotherapy regimen for patients who are not eligible for anthracycline-based regimens and support further evaluation of this regimen as a chemotherapy de-escalation strategy in randomized studies for TNBC.

Trial Registration

ClinicalTrials.gov Identifier: NCT03639948.

Minimal Residual Disease-Directed Adjuvant Therapy for Patients With Early-Stage Colon Cancer: CIRCULATE-US

BACKGROUND

The ability to detect circulating tumor DNA (ctDNA), a novel surrogate for minimal residual disease (MRD) for patients with solid tumors, has significantly evolved over the past decade. Several studies have shown that ctDNA may provide clinical insight into the biological dynamics of MRD. The CIRCULATE-US (NRG-GI008; NCT05174169) trial will aim to address the role of ctDNA for risk stratification to intensify and deintensify adjuvant chemotherapy for patients with early-stage colon cancer.

METHODS

CIRCULATE-US, a prospective phase 2/3 randomized trial, is investigating the molecular dynamics and prognostic role of ctDNA (evaluated by Natera's Signatera assay) for patients with resected colon cancer. Patients with negative postoperative ctDNA will be enrolled in cohort A and randomized to receive either immediate treatment with 5-fluorouracil and folinic acid or capecitabine plus oxaliplatin (FOLFOX6 or CAPEOX; Arm 1) or serial ctDNA surveillance with delayed adjuvant therapy (Arm 2). Patients randomized to Arm 2 with subsequent positive ctDNA results will be enrolled in cohort B for a second randomization to receive either FOLFOX6/CAPEOX (Arm 3) or 5-fluorouracil, folinic acid, oxaliplatin, and irinotecan (FOLFIRINOX; Arm 4) for 6 months. Patients with positive postoperative ctDNA results will be directly enrolled in cohort B and randomized to receive either FOLFOX6/CAPEOX (Arm 3) or FOLFIRINOX (Arm 4). Patients with stage II or stage IIIC colon cancer with positive ctDNA results (tested as standard of care with commercial testing) will be eligible for enrollment in cohort B. The primary end point for cohort A is time to positive ctDNA status for phase 2 and disease-free survival for phase 3 with a noninferiority design. The primary end point for cohort B is disease-free survival for both phase 2 and phase 3 with a superiority design.

DISCUSSION

CIRCULATE-US will aim to understand postoperative ctDNA dynamics in early-stage colon cancer and will investigate escalation and de-escalation approaches by using ctDNA status as a surrogate for MRD status.

The Role of Minimal Residual Disease Testing in Myeloma Treatment Selection and Drug Development: Current Value and Future Applications

Treatment of myeloma has benefited from the introduction of more effective and better tolerated agents, improvements in supportive care, better understanding of disease biology, revision of diagnostic criteria, and new sensitive and specific tools for disease prognostication and management. Assessment of minimal residual disease (MRD) in response to therapy is one of these tools, as longer progression-free survival (PFS) is seen consistently among patients who have achieved MRD negativity. Current therapies lead to unprecedented frequency and depth of response, and next-generation flow and sequencing methods to measure MRD in bone marrow are in use and being developed with sensitivities in the range of 10^-5 to 10^-6 cells. These technologies may be combined with functional imaging to detect MRD outside of bone marrow. Moreover, immune profiling methods are being developed to better understand the immune environment in myeloma and response to immunomodulatory agents while methods for molecular profiling of myeloma cells and circulating DNA in blood are also emerging. With the continued development and standardization of these methodologies, MRD has high potential for use in gaining new drug approvals in myeloma. The FDA has outlined two pathways by which MRD could be qualified as a surrogate endpoint for clinical studies directed at obtaining accelerated approval for new myeloma drugs. Most importantly, better understanding of MRD should also contribute to better treatment monitoring. Potentially, MRD status could be used as a prognostic factor for making treatment decisions and for informing timing of therapeutic interventions. Clin Cancer Res; 23(15); 3980-93. ©2017 AACR.

Evolving Therapies in Acute Myeloid Leukemia: Progress at Last?

Acute myeloid leukemia (AML) is an acquired disease characterized by chromosomal translocations and somatic mutations that lead to leukemogenesis. Systemic combination chemotherapy with an anthracycline and cytarabine remains the standard induction regimen for "fit" adults. Patients who achieve complete remission generally receive postinduction therapy with cytarabine-based chemotherapy or an allogeneic bone marrow transplant. Those unfit for induction chemotherapy are treated with hypomethylating agents (HMAs), low-dose cytarabine, or they are offered supportive care alone with transfusions and prophylactic antimicrobials. The revolution in understanding the genetics of AML, facilitated by next-generation sequencing, has led to many new drugs against driver mutations. Better methods of identification of leukemic blasts have provided us with better means to detect the disease left behind after cytotoxic chemotherapy regimens. This measurable residual disease has been correlated with poorer relapse-free survival, demonstrating the need for novel strategies to eradicate it to improve the outcome of patients with acute leukemias. In this article, we discuss adapting and improving AML therapy by age and comorbidities, emerging targeted therapies in AML, and minimal residual disease (MRD) assessment in AML.

[The prognostic value of evaluation of minimal residual disease using technique of flow cytofluorometry during application of therapy of chronic lymphatic leukemia]

The achievement of molecular remission is associated with increasing of survival of patients with chronic lymphatic leukemia. The important direction of research is seeking of parameters applicable to forecast of response to therapy. The purpose of the study was evaluating prognostic significance of indicator of minimal residual disease detected by technique of flow cytofluorometry of peripheral blood of patients with chronic lymphatic leukemia during therapy application. The sampling included 112 patients with chronic lymphatic leukemia aged from 43 to 82 years. All patients were given treatment consisted of 6 courses of immune chemotherapy combined with fludarabine with cyclophosphan and rituximab. The samples of peripheral blood were analyzed after 3 courses during therapy and after 6 courses after completion of treatment. The cells were analyzed using 5 and 6 color flow cytometry for the purpose of detection of immune phenotype associated with chronic lymphatic leukemia. The evaluation of minimal residual disease was implemented according international standardized protocol (Rawstron A.C. et al. 2007; 21 (5): 956-64). The minimal residual disease negative status was reached in 87 (78%) patients during evaluation of response after 6th course of treatment. The implementation of indicators of residual disease after 3 courses with fludarabine, cyclophosphan and rituximab permitted to sort out two groups of patients with chronic lymphatic leukemia i.e 67 patients with low (< 0.12%) level of minimal residual disease and 45 patients with high (> 0.12%) level of tumor cells. The rate of molecular remission after completion of treatment. in the given groups consisted 100% and 44% correspondingly. The study demonstrates possibilities of early immune phenotype evaluation of minimal residual disease to forecast differences in response to treatment in patients with chronic lymphatic leukemia that makes it possible to avoid undesirable toxicity of therapy or to choose method of consolidation.

Therapy-associated secondary tumors in patients with non-germinomatous malignant germ cell tumors

We report three patients with non-germinomatous malignant germ cell tumor (NGMGCT) who developed therapy-associated secondary tumors. They were diagnosed as having NGMGCT by elevated serum levels of α-fetoprotein (AFP), human chorionic gonadotropin (HCG), or β-HCG. Preoperatively, all patients received a combination of etoposide and platinum-based chemotherapy and radiotherapy; neo-adjuvant therapy (NAT) was followed by complete excision of the residual tumor. Postoperatively, all underwent maintenance chemotherapy and all remained free of NGMGCT without recurrence. However, they developed therapy-associated secondary tumors, i.e. glioblastoma, meningioma, or cavernous angioma after 10.1, 9.8, and 8.2 years, respectively. The patient with glioblastoma died one year after its detection. The other two patients are currently alive; the meningioma was completely removed and the cavernous angioma is being monitored without additional treatment. To the best of our knowledge, therapy-associated secondary tumors in patients treated for NGMGCT are rare.